漏缝地板发酵床对育肥羊养殖气体排放的影响及微生物学机理

为明确漏缝地板发酵床对育肥羊养殖过程氨(NH₃)和温室气体排放特征的影响机制，本研究设置地面和漏缝地板发酵床两个试验处理，测定分析了育肥羊养殖过程NH₃、氧化亚氮(N₂O)、二氧化碳(CO₂)和甲烷(CH₄)的排放特征，并采用宏基因组学解析了影响上述气体排放的微生物学机理。试验结果表明，与地面相比，漏缝地板发酵床能够显著降低育肥羊养殖过程的NH₃排放(P<0.05)，其NH₃排放速率为21.64～58.92 mg·m^-2·h^-1,NH₃累积排放量为86.36±1.06 g·m^-2，减排率达58.60%。漏缝地板发酵床同样也能显著降低育肥羊养殖过程的CH₄排放速率(P<0.05)，其CH₄累积排放量为26.66 g·m^-2，减排率可达64.42%。然而，漏缝地板发酵床会使得...

Effects of slatted floor fermentation bed on gas emissions and microbiological mechanism during fattening lamb breeding

In this study, we aimed at investigating how the slatted fermentation bed impacts ammonia（NH₃）and greenhouse gas emissions, we thus constructed two animal pen types：ground floor and slatted floor and fermentation bed, then investigated the NH₃, N₂O, CO₂, and CH₄ emission characteristics as well as the microbiological mechanisms during fattening sheep breeding using metagenomics. Compared to the ground control, the fermentation bed could significantly reduce the NH₃ emissions（P<0.05）, exhibiting NH₃ emission rates ranging between 21.64-58.92 mg·m^-2·h^-1, cumulative NH₃ emission of 86.36 g·m^-2, and a reduction rate of 58.60%. The slatted floor fermentation bed could also significantly reduce the CH₄ emission rates（P<0.05）, with a cumulative CH₄ emission of 26.66 g·m-2 and a reduction rate of 64.42%. However, the slatted floor fermentation bed could significantly increase the N₂O and CO₂ emissions（P<0.05）, especially those of N₂O, yielding 190.84 times higher values than those of the ground control. The metagenomic analysis results revealed that the relative abundance of beneficial microorganisms, such as that of Salinicoccus, Corynebacterium, Brachybacterium, and Nocardiopsis, displaying salt tolerance and being involved in nitrification and denitrification, significantly increased in the fermentation bed（P<0.05）. Moreover, the relative abundance of key nitrogen conversion genes, such as that of narG, napA, nirS, nirK, norB and nosZ, significantly increased（P< 0.05）, reducing the NH₃ but increasing the N₂O emissions of the fermentation bed. Compared with the ground control, certain anaerobic microorganism populations, such as those of Anaerococus and Anaerococus, were significantly reduced（P<0.05）in the fermentation bed, yielding lower CH₄ emissions. In addition, the higher CO₂ emissions of the fermentation bed were closely related to microbial pyruvate metabolism and tricarboxylic acid cycling.